There are lots of great essays about writing, but I don’t know if any of them are as enjoyable as Shirley Jackson’s “Notes for a Young Writer.” It’s funny, smart, and filled with great advice like the following:
“Not every action needs a qualifying adverb, not every object needs a qualifying adjective. Your reader probably has a perfectly serviceable mental picture of a lion; when a lion comes into your story you need not burden him with adjectives unless it is necessary, for instance, to point out that he is a green lion, something of which your reader might not have a very vivid mental picture.”
That useful passage is followed by this wonderful bit on how to use the wrong word:
Use all the tools at your disposal. The language is infinitely flexible, and your use of it should be completely deliberate. Never forget the grotesque effect of the absolutely wrong words: “He swept her into his arms; ‘I will always love you,’ he giggled.”
You can find this essay in the collection, Come Along with Me, which also includes Jackson’s Experience and Fiction.